Flow control (practice)

Primary exercises

Let’s take the following from a World Health Organization document:

An adult is a person older than 19 years of age unless national law defines a person as being an adult at an earlier age.
An adolescent is a person aged 10 to 19 years inclusive.
A child is a person 19 years or younger unless national law defines a person to be an adult at an earlier age.
However, in these guidelines when a person falls into the 10 to 19 age category they are referred to as an adolescent (see adolescent definition).
An infant is a child younger than one year of age.

The categories can be enumerated as follows:

Implement a function ageGroup which takes age argument (in years) and returns the age group label.

Function template Here is a template of the ageGroup function:

ageGroup <- function( age ) { 
  # age: age given in years
  ...
}

and here are expected results:

ageGroup(0)   # "infant"
ageGroup(10)  # "adolescent"
ageGroup(9)   # "child"
ageGroup(20)  # "adult"
ageGroup(-1)  # should generate an error

To generate the error we request the program to ?stop with an error message.